Article with photocatalytic film

• US 6,582,839 B1
• Filed: 08/31/2000
• Issued: 06/24/2003
• Est. Priority Date: 09/02/1999
• Status: Expired due to Fees

• Current Assignee: Central Glass Company Limited
• Original Assignee: Central Glass Company Limited
• Inventors: Yamamoto, Hideki, Yamazaki, Seiji, Nishida, Yoshihiro, Honjo, Hiroshi
• Primary Examiner(s): Jones, Deborah
• Assistant Examiner(s): Piziali, Andrew T
• Application Number:
  US09/652,660
• Time in Patent Office: 1,027 Days
• Field of Search: 428/428, 428/432, 428/448, 428/702, 428/323, 428/332, 428/334, 428/335, 428/336, 428/426, 428/446, 428/688, 428/689, 428/697, 428/913
• US Class Current: 428/702
• CPC Class Codes: C03C 17/23 Oxides C03C17/02 takes precedence
• CPC Class Codes: C03C 17/2456 Coating containing TiO2
• CPC Class Codes: C03C 17/256 Coating containing TiO2
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
• CPC Class Codes: Y10T 428/263 Coating layer not in excess of 5 mils thick or equivalent
• CPC Class Codes: Y10T 428/264 Up to 3 mils
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

The invention relates to an article having a substrate and photocatalytic film covering the substrate. This film contains (1) a film-forming component including ZrO₂ and SiO₂ and (2) TiO₂ crystals dispersed in the film-forming component. These ZrO₂, SiO₂ and TiO₂ crystals respectively are in amounts of 25-60 wt %, 15-50 wt % and 25-45 wt %, based on the weight of the film. The article is improved in photocatalytic activity, abrasion resistance and chemical resistance by the provision of the film.

Claims

1. An article comprising:

a substrate; and

a photocatalytic film covering said substrate, said film comprising (1) a film-forming component comprising ZrO₂ and SiO₂ and (2) TiO₂ crystals dispersed in said film-forming component, said ZrO₂, said SiO₂ and said TiO₂ crystals respectively being in amounts of 30-60 wt %, 15-45 wt % and 25-45 wt %, based on a weight of said film.

2. An article according to claim 1, wherein a total amount of said ZrO₂, said SiO₂ and said TiO₂ crystals is at least 90 wt %, based on the weight of said film.

3. An article according to claim 1, wherein said film has a thickness of from 50 to 300 nm.

4. An article according to claim 1, wherein said ZrO₂ is in an amount of 30-45 wt %, based on the weight of said film.

5. An article according to claim 1, wherein said SiO₂ is in an amount of 25-45 wt %, based on the weight of said film.

6. An article according to claim 1, wherein said TiO₂ crystals have an average grain size of not greater than 30 nm.

7. An article according to claim 6, wherein said average grain size is not greater than 20 nm.

8. An article according to claim 1, wherein said substrate is a curved glass plate.

9. An article according to claim 1, wherein said article is an automotive window pane having said photocatalytic film on an outer side thereof.

10. An article according to claim 1, wherein said film further comprises at least one member selected from the group consisting of amorphous TiO₂, colloidal silica, Al₂O₃, B₂O₃, SnO₂, Cr ion, V ion, and carbon.

11. An article according to claim 1, wherein said article is produced by a process comprising:

providing a coating liquid comprising a first raw material of said ZrO₂, a second raw material of said SiO₂, and a third raw material of said TiO₂ crystals;

applying said coating liquid to a surface of said substrate, thereby forming thereon a precursory film; and

subjecting said precursory film to a heat treatment at a temperature of 300-700°

C., thereby turning said precursory film into said photocatalytic film.

12. An article according to claim 11, wherein said third raw material is TiO₂ crystal grains having an average grain size of not greater than 20 nm.

13. An article according to claim 11, wherein said first raw material is zirconium chloride or zirconium nitrate.

14. An article according to claim 1, wherein said article is produced by a process comprising:

providing a coating liquid comprising a first raw material of said ZrO₂, a second raw material of said SiO₂, and a third raw material of said TiO₂ crystals;

applying said coating liquid to a surface of said substrate, thereby forming thereon a precursory film; and

subjecting said precursory film to a first baking at a temperature of 560-700°

C., thereby turning said precursory film into said photocatalytic film.

15. An article according to claim 14, wherein said substrate is a glass plate, and wherein said glass plate is bent into a curved glass plate when said precursory film and said glass plate are subjected to said first baking.

16. An article according to claim 14, wherein said substrate is a glass plate, and wherein said glass plate is bent into a curved glass plate after said first baking.

17. An article according to claim 14, wherein, prior to said first baking, said precursory film is subjected to a second baking at a temperature of 300-620°

C.

18. An article according to claim 14, wherein said third raw material is TiO₂ crystal grains having an average grain size of not greater than 30 nm.

19. An article according to claim 14, wherein said first raw material is zirconium chloride or zirconium nitrate.

29. An article according to claim 1, wherein said ZrO₂ is in amount of 30-50 wt %, based on the weight of said film.

20. A process for producing an article, said article comprising:

a substrate; and

a photocatalytic film covering said substrate, said film comprising (1) a film-forming component comprising ZrO₂ and SiO₂ and (2) TiO₂ crystals dispersed in said film-forming component, said ZrO₂, said SiO₂ and said TiO₂ crystals respectively being in amounts of 30-60 wt %, 15-45 wt % and 25-45 wt %, based on a weight of said film,

said process comprising;

providing a coating liquid comprising a first raw material of said ZrO₂, a second raw material of said SiO₂, and a third raw material of said TiO₂ crystals;

applying said coating liquid to a surface of said substrate, thereby forming thereon a precursory film; and

subjecting said precursory film to a heat treatment at a temperature of 300-700°

C., thereby turning said precursory film into said photocatalytic film.

21. A process according to claim 20, wherein said third raw material is TiO₂ crystal grains having an average grain size of not greater than 20 nm.

22. A process according to claim 20, wherein said first raw material is zirconium chloride or zirconium nitrate.

23. A process for producing an article, said article comprising:

a substrate; and

a photocatalytic film covering said substrate, said film comprising (1) a film-forming component comprising ZrO₂ and SiO₂ and (2) TiO₂ crystals dispersed in said film-forming component, said ZrO₂, said SiO₂ and said TiO₂ crystals respectively being in amounts of 30-60 wt %, 15-45 wt % and 25-45 wt %, based on a weight of said film,

said process comprising;

providing a coating liquid comprising a first raw material of said ZrO₂, a second raw material of said SiO₂, and a third raw material of said TiO₂ crystals;

applying said coating liquid to a surface of said substrate, thereby forming thereon a precursory film; and

subjecting said precursory film to a first baking at a temperature of 560-700°

C., thereby turning said precursory film into said photocatalytic film.

24. A process according to claim 23, wherein said substrate is a glass plate, and wherein said glass plate is bent into a curved glass plate when said precursory film and said glass plate are subjected to said first baking.

25. A process according to claim 23, wherein said substrate is a glass plate, and wherein said glass plate is bent into a curved glass plate after said first baking.

26. A process according to claim 23, wherein, prior to said first baking, said precursory film is subjected to a second baking at a temperature of 300-620°

C.

27. A process according to claim 23, wherein said third raw material is TiO₂ crystal grains having an average grain size of not greater than 30 nm.

28. A process according to claim 23, wherein said first raw material is zirconium chloride or zirconium nitrate.